Growth and Development
Growth and development items ask you to separate normal variation from a true red flag, and to know which milestone windows are wide versus narrow.
Core rules
- Use the right chart: WHO standards for birth to 24 months, CDC charts from age 2. A single percentile means little; a child crossing two major percentile lines (75th to 25th) warrants evaluation.
- Head circumference is measured until about 2–3 years and is the most sensitive early screen for hydrocephalus and microcephaly.
- Windows: social smile 6–8 weeks; head control 4 months; sits unsupported 6–8 months; walks independently 12–15 months (up to 18 months remains normal); 2–3 meaningful words by 15–18 months; 50 words and 2-word phrases by 24 months; tricycle at 3 years; hops on one foot at 4; ties shoes at 5.
- For any infant born before 37 weeks, use adjusted age until 24 months: chronological age minus weeks of prematurity.
- Piaget: sensorimotor (0–2), preoperational (2–7), concrete operational (7–11), formal operational (11+). Erikson: trust vs mistrust in infancy, autonomy vs shame in toddlerhood.
Worked example
An 18-month-old born at 32 weeks is not walking. Adjusted age is about 16 months, and walking is expected by 18 months. The finding sits inside the normal window; the correct action is continued surveillance at the next visit plus a focused exam for tone, symmetry, and hip abduction, not immediate referral. If the child were 20 months adjusted and still not walking, a developmental referral would be indicated.
Traps
- Declaring delay from one missed milestone; windows are broad.
- Forgetting corrected age in an ex-preterm infant.
- Calling a low growth percentile failure to thrive without a trend over time.
- Missing regression - loss of previously acquired skills is always abnormal and needs prompt workup.